The Galata Tower (Galata Kulesi in Turkish) — called Christea Turris (the Tower of Christ in Latin) by the Genoese — is a medieval stone tower in the Galata district of Istanbul, Turkey, just to the north of the Golden Horn. One of the city's most striking landmarks, it is a high, cone-capped cylinder that dominates the skyline and affords a panoramic vista of Old Istanbul and its environs. The nine-story tower is 66.90 meters tall (62.59 m without the ornament on top, 51.65 m at the observation deck), and was the city's tallest structure when it was built. The elevation at ground level is 35 meters above sea-level. The tower has an external diameter of 16.45 meters at the base, an 8.95 meters diameter inside, and walls that are 3.75 meters thick. The tower was built as Christea Turris (Tower of Christ) in 1348 during an expansion of the Genoese colony in Constantinople. The Galata Tower was the tallest building in Istanbul at 219½ feet (66.9 m) when it was built in 1348. Starting from 1717 the Ottomans began to use the tower for spotting fires in the city. In 1794, during the reign of Sultan Selim III, the roof of the tower made of lead and wood, and the stairs were severely damaged by a fire. Another fire damaged the building in 1831, upon which a new restoration work took place.

Fires were announced by means of flags in Bayezid and Galata Fire Towers as follows:

Anatolia – bound: Green lamb at night – green triangle flag at day time. In case of fires in two or three regions at the same time, flags belonging to each destination were pulled together.

İcadiye tower was an outbuilding of a manor house in Vaniköy in the era of Mahmud the Second. The tower burned during the Crimean war.

Beyazıt Tower, also named Seraskier Tower, from the name of the Ottoman ministry of War, is an 85 metre tall fire-watch tower located in the courtyard of Istanbul University's main campus (formerly Ottoman Ministry of War) on Beyazıt Square (known as the Forum Tauri in the Roman period) in Istanbul, Turkey, on top of one of the "seven hills" which Constantine the Great had built the city, following the model of Rome.

Beyazıt Tower was ordered by the Ottoman Sultan Mahmud II (1808-1839), and designed by Senekerim Balyan who built it of stone in 1828 on the place of the original wooden Beyazıt Tower which was destroyed in a fire and was constructed earlier by the architect's brother, Krikor Balyan.

The first fire-watch tower in Beyazıt was built of timber in 1749, but it was burnt down during the 1756 Great Fire of Cibali. It was replaced by another timber tower on the same location, which was destroyed following the riots stirred by Sultan Mahmud II's decision to dissolve the Janissary Corps in 1826. The same year, another wooden tower was erected on the plot, designed and built by the palace architect Krikor Balyan, which was again set on fire by adherents of the Janissaries. Finally, the current tower, made of stone, was built in 1828 by Senekerim Balyan in Ottoman Baroque style.

The stone tower originally had a single floor of around 50 m² at the top for fire watching, which was reached through a wooden staircase of 180 steps. This watch room has 13 round arched windows. Initially, the tower had a timber roof in the form of a cone. In 1849, three floors in octagonal plan with round windows were added on the top section: one for signaling, one for signal baskets and the last one for flags. The smaller diameter of the highest three floors makes space for a terrace at the second floor. In 1889, an iron pole of 13 meters was erected on the roof. The tower was partly damaged by the earthquake of 1889 and was subsequently restored. At present, the tower has a stone roof and a wooden staircase of 256 steps.

Fire was an important threat for Istanbul and caused numerous wide scale disasters, largely because most houses in the Old City's historic quarters were made of timber. Beyazıt Tower, Galata Tower and İcadiye Fire Tower (on Vaniköy Hill) were used for spotting fire threats, as they commanded long distance views of the city from above. The entire Old City (Yedikule, Topkapı, Kocamustafapaşa, Fatih, Beyazıt), the cross-section of the Golden Horn districts (Fener, Balat, Eminönü) and those of the Bosphorus (Tophane, Beşiktaş, Ortaköy), the entrance of the Sea of Marmara (Üsküdar, Kadıköy) and even the Princes' Islands towards the southeast of the city were within the range of watch sight from Beyazıt Tower.

Fire was signaled at daytime by lowering baskets and at night by lighting colored lamps. The number of the baskets or the number and the color of the lamps indicated the location, i.e. in which district of Istanbul the fire outbroke. As a response, the Watch Tower of Icadiye on the Anatolian side of the Bosphorus then fired 7 volleys to inform the citizens of the fire. 20 fire fighters were stationed in the Beyazıt Tower until 1923. In 1997, the structure underwent a thorough restoration.[1]

Beyazıt Tower is still in use today as a watch-tower as well as for signaling weather forecast and maritime navigation information to the ships on the Golden Horn at night. The tower lost its importance with the development of advanced communications technology. Recently, two firefighters in three shifts are stationed in the tower for guarding purposes only. Since 1972, special permission is required to enter the tower.